1. Field of the Invention
The present general inventive concept relates to an image forming apparatus and a method of driving the same. More particularly, the present general inventive concept relates to an array print head type image forming apparatus including a plurality of print heads arranged in a width direction of a paper sheet and a method of driving the same.
2. Description of the Related Art
In general, image forming apparatuses, such as ink-jet printers, spit minute droplets of printing inks in desired positions on printing media such as paper sheets, fabrics, or the like, to print images of predetermined colors on surfaces of the printing media.
General ink-jet printers include ink cartridges which move in a direction orthogonal to a direction along which paper sheets are transferred, i.e., in a width direction of the paper sheets, and print images on the paper sheets. However, such an ink-jet printer has a slow printing speed.
Ink cartridges having a plurality of print heads arranged throughout a width direction of a paper sheet have been recently adopted to provide ink-jet printers capable of printing images at a fast speed without moving ink cartridges back and forth. Such ink-jet printers are also called array print head type ink-jet printers.
A conventional array print head type ink cartridge includes a plurality of ink tanks, a plurality of negative pressure adjusters, a plurality of print heads, and an ink channel unit. The plurality of ink tanks store printing inks. The plurality of negative pressure adjusters are respectively connected to the plurality of ink tanks. The plurality of print heads are arranged in a predetermined pattern in a width direction of a printing medium. The ink channel unit supplies the printing inks from the plurality of ink tanks to the plurality of print heads.
The plurality of ink tanks are installed in a frame and respectively store inks of several colors, for example, yellow (Y), magenta (M), cyan (C), and black (B) inks.
The plurality of negative pressure adjusters are installed underneath the frame to be respectively connected to the plurality of ink tanks. The plurality of negative pressure adjusters generate negative pressures to prevent the inks from leaking.
The ink channel unit is connected to the plurality of negative pressure adjusters and feeds the plurality of print heads with the inks which flow from the plurality of ink tanks into the ink channel unit through the plurality of negative pressure adjusters.
The plurality of print heads are arranged in the predetermined pattern on a front surface of the ink channel unit to be attached to the ink channel unit. Each of the plurality of print heads includes a plurality of nozzles through which the inks are spat. The inks fed from the ink channel unit are spat through the nozzles onto a printing medium so as to print an image on the printing medium. In particular, the nozzles are classified by colors. In general, the nozzles are sequentially arranged by colors in a direction along which paper sheets are transferred.
An array print head type image forming apparatus as described above has a considerably increased printing speed and a simplified structure, but has the following problems.
In order to wipe a plurality of print heads arranged in the width direction of the paper sheet, a blade must be transferred in either a width direction of a paper sheet or a direction along which the paper sheet is transferred. If the blade is transferred in the width direction of the paper sheet, the blade possesses a small surface area in which the plurality of print heads are wiped. Thus, a large amount of ink sticks to the blade during the wiping process. As a result, a normal wiping operation is not performed, and a large amount of time is required for wiping.
Accordingly, a method of moving a blade lengthened in a width direction of a paper sheet toward a direction along which the paper sheet is transferred in order to wipe a plurality of print heads has been suggested. If print heads are wiped using such a method, inks of different colors are pushed into color nozzles sequentially arranged in a direction along which a paper sheet is transferred. Thus, the inks of different colors are mixed. As a result, quality of a printed image becomes deteriorated.
Therefore, a method of rapidly and clearly wiping print heads and preventing ink colors from being mixed is required.